Wifi constantly disconnecting

I just set up a new account at a new address. Everything was working perfectly for a few days with the black gateway i got at the xfinity store. I switched the gateway to the new one i got in the mail, which is the new generation white one. Now the WiFi doesn't work. Whatever device tries to connect to it is disconnected after a few seconds. Phone, laptop, pc, you name it. The Ethernet is working fine from the back of the gateway. A friend just got a new account and got the new white gateway and the WiFi is doing the same thing.

What is going on?